Multiple Choice Questions (MCQ) topic quiz 3.2 Physical Chemistry Instructions and answers for teachers These instructions cover the learner activity section which can be found on page 8. This Lesson Element supports OCR AS and A Level Chemistry A. When distributing the activity section to the learners either as a printed copy or as a Word file you will need to remove the teacher instructions section.
The Activity This Lesson Element is a teaching and learning resource containing 10 multiple choice questions (MCQs) on the theme of physical chemistry. Some questions might require synoptic thinking, using knowledge and ideas from various topics across the full A Level content. This resource can be used to test and consolidate understanding at the end of a topic or to revisit and refresh knowledge at a later point in the course.
Learning Outcomes This lesson element relates to the specification learning outcomes 3.2.1(d), 3.2.1(e), 3.2.1(f), 3.2.1(g), 3.2.2(a), 3.2.2(c), 3.2.2(d), 3.2.2(f), 3.2.2(g), 3.2.3(a), 3.2.3(b), 3.2.3(c), 3.2.3(f).
Introduction Multiple choice questions allow rapid coverage of a wide range of sub-topics. Contrary to a widespread belief among students, multiple choice questions are not necessarily easy – they can be easy, moderate or difficult. The questions are written so that the incorrect answers are plausible distractors based on common errors or misconceptions. The questions in this quiz cover topics mainly from specification sections: 3.2 Physical Chemistry.
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Multiple Choice Questions (MCQ) topic quiz - answers 1.
Which of the following is not a standard condition? A
298 K
Incorrect, this is a common ambient temperature.
B
100 kPa
Incorrect, this is known as standard pressure.
C
100 atm
Correct answer. 1 atmosphere is approximately 100 kPa.
D
1 mol dm–3 solutions
Incorrect, this is a condition most commonly seen in electrochemical cells. Your answer
2.
Which is the equivalent to the formation of carbon dioxide? A
combustion of hydrogen(g)
Incorrect, this forms water.
B
complete combustion of carbon(s)
Correct answer. Formed from its elements in their standard states, identical to CO2 formation.
C
complete combustion of propane(l)
Incorrect, this forms carbon dioxide and water.
D
incomplete combustion of propane(g)
Incorrect, this forms carbon monoxide and water. Your answer
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C
2
B
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3.
15 g of octane is burned and used to heat 50 cm3 of water by 15 oC. What is the amount of energy transferred to the water? Assume a water density of 1 g cm–3 and a specific heat capacity of 4.18 J g–1 K–1. A
940.5 J
Incorrect, learners have used the mass of octane, not the mass of water heated.
B
3135 J
Correct answer, 50 × 4.18 × 15 = 3135 J
C
940.5 kJ
As above but they have also used the incorrect units.
D
3135 kJ
Incorrect, they have misinterpreted the units in the equation. Your answer
4.
Use the bond enthalpies to determine the ∆cH for methane. Bond
Bond Enthalpy (kJ mol–1)
C–C
350
C=C
611
C=O
732
C–O
350
C–H
410
O–H
460
O=O
498
A
–1664 kJ mol–1
Incorrect, they have not accounted for 2 O=O bonds.
B
–744 kJ mol–1
Incorrect, they have not fully balanced or accounted for the number of molecules.
C
–668 kJ mol–1
Correct answer, ((4 × 410) + (2 × 298)) – ((2 × 732) + (4 × 460)).
D
+252 kJ mol–1
Incorrect, they have not accounted for 4 O–H bonds. Your answer
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B
3
C
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5.
Which reaction is not used to make a Hess cycle for the following reaction? C2H4(g) + H2O(l) C2H5OH(l) A
∆fH ethanol
Incorrect, this is needed for the Hess cycle. ∆fH ethanol – ∆fH ethane – ∆cH hydrogen = ∆rH.
B
∆cH ethene
Correct answer.
C
∆cH hydrogen
Incorrect, this needed for the Hess cycle.
D
∆fH ethene
Incorrect, this needed for the Hess cycle. Your answer
6.
Which does not increase rate by affecting the number or nature of collisions? A
adding a catalyst
Correct answer. This decreases Ea rather than affecting the number of collisions.
B
increasing the pressure
Incorrect, higher pressure means more collisions.
C
increasing the surface area
Incorrect, greater surface area means more collisions.
D
increasing the temperature
Incorrect, this increases number of collisions and the collision energy. Your answer
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B
4
A
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7.
What is the meaning of a heterogeneous catalyst? A
A catalyst which stays the same throughout the reaction.
Incorrect.
B
A catalyst which changes throughout the reaction.
Incorrect, a catalyst is not used up by the reaction.
C
A catalyst in the same state as the reactants.
Incorrect, homo = same, they have remembered the name incorrectly.
A catalyst in a different state to the reactants.
Correct answer, iron in the Haber process is an example. Your answer
8.
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What does the shaded area represent?
A
The number of additional molecules which are likely to react at a higher temperature.
Correct answer.
B
The number of molecules which are likely to react at a lower temperature.
Incorrect. They may have mixed up which curve represents high and low temperature.
C
The number of additional molecules which are likely to react in the presence of a catalyst.
Incorrect. A catalyst question comes up commonly but will show two Ea lines.
D
The number of additional molecules which are likely to react in the presence of a catalyst at higher temperature.
Incorrect.
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A
Your answer 9.
Which does not describe a reaction at equilibrium? A
Forward and backward reactions occur at equal rate.
Incorrect.
B
The system must be closed.
Incorrect, additional reactants or products will disrupt equilibrium.
C
Kc increases as the reaction progresses.
Correct answer, Kc is constant while temperature is maintained.
D
Concentrations of reactants and products are constant.
Incorrect. Concentrations are constant because forward and backward reactions are equal. Your answer
10.
Which statement(s) is/are true regarding the reaction below? N2(g) + 3H2(g)
2NH3(g)
∆H = –92 kJ mol–1
1)
An increase in pressure will increase the rate and shift the equilibrium to the right.
2)
An increase in temperature will increase the rate and shift the equilibrium to the right.
3)
A catalyst will increase the rate and shift the equilibrium to the right.
A
1,2 and 3
Incorrect.
B
only 1 and 2
1 is true, but increasing temperature will move the equilibrium to the left.
C
only 2 and 3
A catalyst has no effect on the position of the equilibrium.
D
only 1
Correct answer, increased pressure increases rate for gases and moves the equilibrium towards the side with fewest moles of gas. Your answer
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C
6
D
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This formative assessment resource has been produced as part of our free Chemistry teaching and learning support package. All the Chemistry teaching and learning resources, including delivery guides, topic exploration packs, lesson elements and more are available on the qualification webpages. If you are looking for examination practice materials, you can find Sample Assessment Materials (SAMs) and a link to the Practice Papers on the qualification webpages: Chemistry A, Chemistry B. We’d like to know your view on the resources we produce. By clicking on ‘Like’ or ‘Dislike’ you can help us to ensure that our resources work for you. When the email template pops up please add additional comments if you wish and then just click ‘Send’. Thank you. If you do not currently offer this OCR qualification but would like to do so, please complete the Expression of Interest Form which can be found here: www.ocr.org.uk/expression-of-interest
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Multiple Choice Questions (MCQ) topic quiz 3.2 Physical Chemistry Learner Activity 1.
Which of the following is not a standard condition? A
298 K
B
100 kPa
C
100 atm
D
1 mol dm–3 solutions Your answer
2.
Which is the equivalent to the formation of carbon dioxide? A
combustion of hydrogen(g)
B
complete combustion of carbon(s)
C
complete combustion of propane(l)
D
incomplete combustion of propane(g) Your answer
3.
15 g of octane is burned and used to heat 50 cm3 of water by 15 oC. What is the amount of energy transferred to the water? Assume a water density of 1 g cm–3 and a specific heat capacity of 4.18 J g–1 K–1. A
940.5 J
B
3135 J
C
940.5 kJ
D
3135 kJ Your answer
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4.
Use the bond enthalpies to determine the ∆cH for methane. Bond
Bond Enthalpy (kJ mol–1)
C–C
350
C=C
611
C=O
732
C–O
350
C–H
410
O–H
460
O=O
498
A
–1664 kJ mol–1
B
–744 kJ mol–1
C
–668 kJ mol–1
D
+252 kJ mol–1 Your answer
5.
Which reaction is not used to make a Hess cycle for the following reaction? C2H4(g) + H2O(l) C2H5OH(l) A
∆fH ethanol
B
∆cH ethene
C
∆cH hydrogen
D
∆fH ethene Your answer
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6.
Which does not increase rate by affecting the number or nature of collisions? A
adding a catalyst
B
increasing the pressure
C
increasing the surface area
D
increasing the temperature Your answer
7.
What is the meaning of a heterogeneous catalyst? A
A catalyst which stays the same throughout the reaction.
B
A catalyst which changes throughout the reaction.
C
A catalyst in the same state as the reactants.
D
A catalyst in a different state to the reactants. Your answer
8.
What does the shaded area represent?
A
The number of additional molecules which are likely to react at a higher temperature.
B
The number of molecules which are likely to react at a lower temperature.
C
The number of additional molecules which are likely to react in the presence of a catalyst.
D
The number of additional molecules which are likely to react in the presence of a catalyst at higher temperature. Your answer
9.
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Which does not describe a reaction at equilibrium?
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A
Forward and backward reactions occur at equal rate. The system must be closed.
B C
Kc increases as the reaction progresses.
D
Concentrations of reactants and products are constant. Your answer
10.
Which statement(s) is/are true regarding the reaction below? N2(g) + 3H2(g)
2NH3(g)
∆H = –92 kJ mol–1
1)
An increase in pressure will increase the rate and shift the equilibrium to the right.
2)
An increase in temperature will increase the rate and shift the equilibrium to the right.
3)
A catalyst will increase the rate and shift the equilibrium to the right.
A
1,2 and 3
B
only 1 and 2
C
only 2 and 3
D
only 1 Your answer
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